documentation: add some internals documentation about bid merge
This is an important algorithm that was only documented on the wiki so far.
Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.
Differential Revision: https://phab.mercurial-scm.org/D8711
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo y > y
$ echo z > z
$ hg commit -qAm xy
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ cd shallow
Verify corrupt cache handling repairs by default
$ hg up -q null
$ chmod u+w $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ echo x > $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ hg up tip
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
Verify corrupt cache error message
$ hg up -q null
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> validatecache=off
> EOF
$ chmod u+w $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ echo x > $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ hg up tip 2>&1 | egrep "^RuntimeError"
RuntimeError: unexpected remotefilelog header: illegal format
Verify detection and remediation when remotefilelog.validatecachelog is set
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> validatecachelog=$PWD/.hg/remotefilelog_cache.log
> validatecache=strict
> EOF
$ chmod u+w $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ echo x > $CACHEDIR/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$ hg up tip
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cat .hg/remotefilelog_cache.log
corrupt $TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0 during contains
Verify handling of corrupt server cache
$ rm -f ../master/.hg/remotefilelogcache/y/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
$ touch ../master/.hg/remotefilelogcache/y/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
$ clearcache
$ hg prefetch -r .
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ test -s ../master/.hg/remotefilelogcache/y/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
$ hg debugremotefilelog $CACHEDIR/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
size: 2 bytes
path: $TESTTMP/hgcache/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
key: 076f5e2225b3
node => p1 p2 linknode copyfrom
076f5e2225b3 => 000000000000 000000000000 f3d0bb0d1e48